'Sirio' was an Italian convoy operation from ports of southern Italy to Tripoli in North Africa with reinforcements, weapons, ammunition and other supplies for the Axis forces facing the British-led forces in North Africa (15/21 March 1942).
Launched from Naples, the operation involved the 7,744-ton German transport Reichenfels and 6,339-ton Italian transport Vettor Pisani, the first escorted by the torpedo boats Polluce and Lince, and the second by the destroyers Ugolini Vivaldi, Lanzerotto Malocello, Emanuele Pessagno and Nicolo Zeno, and torpedo boats Giuseppe Sirtori, Pallade and Generale Marcello Prestinari. Close cover was provided by the light cruiser Emanuele Filiberto Duca d’Aosta and destroyers Scirocco and Grecale.
On 16 March the British submarine Unbeaten scored a torpedo hit on Vettor Pisani, but was denied success by the failure of the weapon’s impact fuse. Both transports reached Tripoli on 18 March without further incident, and the escort and covering forces turned back toward Taranto to protect other ships making for North African ports. Bosforo had left Taranto on 15 March but was delayed at Navarino (Pylos in Greek) on the west coast of the Peloponnese between 17 and 19 March before making passage to Benghazi, which she reached on 21 March. On 17 March Salona and Achaia left Tripoli bound for Benghazi, escorted by Calliope, and the 1,778-ton German freighter Achaia fell victim to an Italian mine shortly after departing Tripoli.
On 18 March Monreale and Nino Bixio left Tripoli escorted by the destroyers Ugolini Vivaldi, Emanuele Pessagno, Lanzerotto Malocello and Nicolo Zeno, as well as the torpedo boat Pallade, and reached Naples safely on 20 March.